Private Oberlin Herbert Gray was born in Bushy Park, Tasmania, on 11 October 1890 to parents Frederic and Bithiah Gray. He was one of five brothers. Oberlin grew up in the Hobart area and was educated at The Friends High School. At the outbreak of the First World War, he was working as a farmer. Oberlin and his family were Quakers, and conscientiously were not able to 'take up arms'. However, as Oberlin wished to serve, he joined the medical corps.

On 30 December 1914, at 24, Oberlin Herbert Gray enlisted with the 3rd Australian Field Ambulance. He embarked from Melbourne on HMAT Runic in February 1915, disembarking in Egypt on 3 April 1915. Oberlin served as a stretcher bearer for three and a half years, first in Gallipoli, then in France. He wrote down his experiences of the war in a series of diaries, which are now part of the Private Records Collection at the Australian War Memorial.

Oberlin Herbert Gray almost survived the war, but was hit by a shell near Daours, Somme, France (7 miles east of Amiens) on 23 August 1918. His younger brother, Private Frederic Oliver Gray, who joined the 3rd Australian Field Ambulance as a stretcher bearer in May 1916, was with Oberlin when he was hit. Frederick Oliver carried Oberlin out of the field, and remained with him until he was put in an ambulance and taken to the 55th Casualty Clearing Station. Oberlin died a few hours later, on 24 August 1918. His grave is in Daours Communal Cemetery Extension. He is buried in Plot 6 Row B No. 10 grave.